Java EE 6 Overview

Reza RahmanExpert Group Member, Java EE 6Resin Container DeveloperAuthor, EJB 3 in Actionreza@caucho.com

Java EE 6: New Horizons

Java EE 5• Annotations, convention-over-configuration, freedom from XML

• EJB 3, JPA, JSF, JAX-WS

Java EE 6• Pruning: Cutting the dead wood

• Profiles: Enabling lightweight application servers

• Innovation: New APIs, new features, further ease-of-use

Managed beans, CDI, JSF 2, EJB 3.1, JPA 2, Servlet 3, JAX-RS, bean validation

Pruning

The goal is to “deprecate” APIs that are out-of-date or have been superseded

Pruned APIs:• JAX-RPC: Superseded by JAX-WS

• EJB 2.x Entity Beans CMP: Dropped in favor of JPA

• JAXR: UDDI not well used

• Java EE Application Deployment (JSR-88): Poor support

Profiles

Specific sub-sets of Java EE APIs intended for specific types of applications

Each Profile is fully integrated and “just works” out-of-the-box, although integrating add-ons is still possible

Makes creating modular, lightweight Java EE compliant application servers a lot easier (such as Resin which only implements the Java EE 6 Web Profile)

Only one Profile, the “Web Profile” is initially planned

Java EE 6 Web Profile

Bean validation

JCA

JACC

JAXB

JAX-RS

JAX-WS

JavaMail

JMS

JTA

JPA 2

EJB 3.1*

CDI

JSF 2

Servlet 3

Full ProfileWeb ProfileAPI

Major API ChangesContexts and Dependency Injection (CDI)• Next generation dependency injection

Java Server Faces (JSF) 2• Ease-of-use, technology adoption, new features

Enterprise Java Beans (EJB) 3.1• Ease-of-use, new features

Java Persistence API (JPA) 2• More flexibility, new features

Servlet 3• Ease-of-use, new features

Java API for RESTful Web Services (JAX-RS)• REST based web services in addition to SOAP support in JAX-WS

Bean Validation• Expressing application constraints declaratively

Contexts and Dependency InjectionType-safe generic dependency injection

Automatic context management

Unifies JSF, JPA and EJB 3 programming models

Conversations

Interceptors/decorators

Annotations meta-programming

Portable extensions

JSF Using CDI<h:form>

<table><tr>

<td>Bidder</td><td><h:inputText value="#{bid.bidder}"/></td>

</tr><tr>

<td>Item</td><td><h:inputText value="#{bid.item}"/></td>

</tr><tr>

<td>Bid Amount</td><td><h:inputText value="#{bid.price}"/></td>

</tr></table>...<h:commandButton type="submit" value="Add Bid"

action="#{placeBid.addBid}"/>...

</h:form>

JPA Entity as JSF Model@Entity@Table(name=“BIDS”)public class Bid {

@Id@GeneratedValue@Column(name=“BID_ID”)private Long id;private String bidder;private String item;

@Column(name=“BID_PRICE”)private Double price;...

}

EJB 3.1 Session Bean as JSF Event Handler@Stateful @RequestScoped @Namedpublic class PlaceBid {

@PersistenceContextprivate EntityManager entityManager;

@Produces @Namedprivate Bid bid = new Bid();

@Inject @Utilityprivate CurrencyTools tools;

@Auditedpublic void addBid() {

bid.setPrice(tools.round(bid.getPrice()));entityManager.persist(bid);

}}

CDI Managed Bean with Qualifier@Retention(RUNTIME)@Target({TYPE, METHOD, FIELD, PARAMETER})@Qualifierpublic @interface Utility {}

@Utility@ApplicationScopedpublic class DefaultCurrencyTools

implements CurrencyTools {...public double round(double value) {

BigDecimal converter = new BigDecimal(Double.toString(value));

converter = converter.setScale(DECIMAL_PLACES, BigDecimal.ROUND_HALF_UP);

return converter.doubleValue();}...

}

CDI Interceptor@InterceptorBindingType@Target({TYPE, METHOD})@Retention(RUNTIME)public @interface Audited {}

@Audited @Interceptorpublic class AuditInterceptor {

@AroundInvokepublic Object audit(InvocationContext context)

throws Exception {System.out.println("Entering: "

+ context.getMethod().getName());System.out.println(" with args: "

+ context.getParameters());return context.proceed();

}}

Java Server Faces 2First-class support for Facelets as view/custom components/templates

Annotation-driven configuration

Ajax support in the JSF life-cycle

Bookmarking/navigation/parameters

Resources

EL parameters

API/Component improvements

Facelet Components<html xmlns="http://www.w3.org/1999/xhtml"

xmlns:h="http://java.sun.com/jsf/html"xmlns:f="http://java.sun.com/jsf/core"xmlns:ez="http://java.sun.com/jsf/composite/ezcomp">

<h:head><title>A simple example of EZComp</title>

</h:head><h:body><h:form>

<ez:loginPanel id="loginPanel"><f:actionListener for="loginEvent"

binding="#{bean.loginEventListener}" /></ez:loginPanel>

</h:form></h:body></html>

Facelet Custom Component<html xmlns="http://www.w3.org/1999/xhtml"

xmlns:h="http://java.sun.com/jsf/html"xmlns:f="http://java.sun.com/jsf/core"xmlns:ui="http://java.sun.com/jsf/facelets"xmlns:composite="http://java.sun.com/jsf/composite">

<body><composite:interface><composite:actionSource name="loginEvent" />

</composite:interface><composite:implementation><p>Username: <h:inputText id="usernameInput" /></p><p>Password: <h:inputSecret id="passwordInput" /></p><p><h:commandButton id="loginEvent" value="login"/>

</composite:implementation></body></html>

JSF Annotations@ManagedBean(name=“accountCreator")@RequestScopedpublic class AccountCreatorBean {

@ManagedProperty(value="#{user}")private User user;

@EJBprivate AccountService accountService;...public String createAccount() {

...}

}

Enterprise Java Beans 3.1EJBs are managed beans with additional services like transactions

Singleton Beans with concurrency control

Cron-style declarative and programmatic Timers

Asynchronous bean invocation

Simplified WAR packaging

Embedded Containers/Testing support

EJB Lite

Cron-like Declarative Timers@Statelesspublic class NewsLetterGeneratorBean {

@Resourceprivate Session mailSession;

@Schedule(second="0", minute="0", hour="0",dayOfMonth="1", month="*", year="*")

public void generateMonthlyNewsLetter() {...

}}

Asynchronous Session Bean@Statelesspublic class OrderBillingBean {

...@Asynchronouspublic Future<BillingStatus> billOrder(Order order) {

try {bill(order);return new AsyncResult<BillingStatus>(

BillingStatus.COMPLETE);} catch (BillingException be) {

return new AsyncResult<BilllingStatus>(BillingStatus.BILLING_FAILED);

}}...

}

Asynchronous Invocation Client@EJBprivate OrderBillingBean orderBilling;...Order order = new Order();...Future<BillingStatus> future = orderBilling.billOrder(order);...BillingStatus status = future.get();...if (status == BillingStatus.COMPLETE) {

notifyBillingSuccess(order);} else if (status == BillingStatus.BILLING_FAILED) {

notifyBillingFailure(order);}

Java Persistence API 2Object-relational mapping enhancements• Embedded objects, collections, maps and ordered lists• Unidirectional one-to-many mapping• Join tables for one-to-one, many-to-one

Query and EntityManager API enhancements• First result, max result, unwrapping, typed results, detach entities

JPQL enhancements• CASE, NULLIF, COALESCE

Criteria API/Meta-model

Second-level caching

Pessimistic locking

Mapping Collections@Entity@Table(name=“USERS”)public class User {

@Id@GeneratedValue@Column(name=“USER_ID”)public long userId;public String userName;@Column(name=“BIRTH_DATE”)public Date birthDate;...@ElementCollection@CollectionTable(name=”ALIASES”)@Column(name=”ALIAS”)public Set<String> aliases;

@ElementCollectionpublic Map<String, String> photos;

}

Unidirectional One-to-Many Relationship@Entitypublic class User {

@Id @GeneratedValuepublic long id;public String userName;...@OneToMany@JoinColumn(name=“USER_ID")public Set<Phone> phones;

}

@Entitypublic class Phone {

@Id @GeneratedValuepublic long id;public String type;public String number;...

}

Criteria APICriteriaBuilder criteriaBuilder =

entityManager.getCriteriaBuilder();CriteriaQuery<User> criteriaQuery =

criteriaBuilder.createQuery(User.class);Root<User> user = criteriaQuery.from(User.class);criteriaQuery.select(user).where(criteriaBuilder.equal(

user.get(“firstName"), “John”),criteriaBuilder.equal(

user.get(“lastName"), “Smith”));

SELECT userFROM User userWHERE user.firstName = ‘John’AND user.lastName = ‘Smith’

Servlet 3

Annotations from the ground-up

Modular web.xml fragments in framework library jars

Programmatic addition of Servlets, Filters and Listeners through the ServletContext

Servlet container initializers

Asynchronous processing support in Servlets

Servlet Annotations@WebServlet(name=“PlaceBidServlet”

urlPatterns={“/bid”, “/place-bid”})public class PlaceBidServlet extends HttpServlet {

@EJBprivate PlaceBid placeBid;

public void doGet(HttpServletRequest request,HttpServletResponse response) {

Bid bid = new Bid();...placeBid.placeBid(bid);...

}}

Programmatic Servlet Addition@WebListenerpublic class ActionBazaarListener

implements ServletContextListener {public void contextInitialized(

ServletContextEvent event) {ServletContext context = event.getServletContext();ServletRegistration registration

= context.addServlet(“PlaceBidServlet",“actionBazaar.PlaceBidServlet");

registration.addMapping(“PlaceBidServlet",new String[]{"/place-bid"});

}}

Java API for RESTful Web Services

Web services through REST instead of SOAP

REST counterpart of JAX-WS

Gets rid of low-level code so you can focus on core logic

Annotations from the ground-up

Integrated with CDI and EJB

JAX-RS with Session Bean@Stateless@Path("/webservices")public class PlaceBidBean {

@PersistenceContextprivate EntityManager entityManager;

@PUT@Path("/bid/{bidder}")public void placeBid(

@PathParam(“bidder")String bidder,@QueryParam(“item")String item,@QueryParam(“bid_price")Double bidPrice) {entityManager.persist(

new Bid(bidder, item, bidPrice));}

}

Bean Validation

Specify constraints only once across application layers

Constraint• Restriction on a bean, field or property

• Not null, between 10 and 45, valid email, etc

• Evaluated automatically by a framework

Useful in other Java SE/Java EE APIs• JSF 2

• JPA 2

JPA Entity with Bean Validation@Entity@Table(name=“BIDS”)public class Bid {

@Id@GeneratedValue@Column(name=“BID_ID”)public Long id;

@NotNull@Size(min=5, max=30)public String bidder;

@NotNull@Size(min=10, max=200)public String item;

@Column(name=“BID_PRICE”)@NotNull@Min(value=0.0, message=“Price negative”)public Double price;

}

Summary

Pruning• Chopping dead wood

• JAX-RPC, EJB 2.x Entity Beans, JAXR, JSR-88, JSR-77

Profiles• Web profile geared towards majority of Java EE applications

• Lightweight, modular application servers (e.g. Resin)

Innovation• Managed beans, CDI, JSF 2, EJB 3.1, JPA 2, Servlet 3, JAX-RS,

bean validation

ReferencesIntroducing Java EE 6• http://java.sun.com/developer/technicalArticles/JavaEE/JavaEE6Overvie

w.html

Java EE 6 Tutorial• http://java.sun.com/javaee/6/docs/tutorial/doc/

GlassFish• http://java.sun.com/javaee/community/glassfish/

Resin• http://www.caucho.com/projects/resin/

Java EE 6 Code Examples• http://java.sun.com/javaee/reference/code/